1. Field of the Invention
The present invention relates to a connection device for pipelines.
2. Description of Related Art
One such connection device is described in document EP 0 616 161 B1. The retaining element of this device is configured as a toothed ring that has a plurality of radial, tooth-like, retaining arms which are connected to each other via peripheral connection sections. This known design should provide that the toothed ring is mounted freely movable with its outer circumferential area inside the connecting element, such that the peripheral connection sections can be elastically deformed, so that each tooth as such is not deformed on insertion of the line end but can swivel around each of the two adjacent peripheral connection sections. This design consequently requires a movable mounting of the toothed ring that ensures freedom of movement in its external circumferential area. This free mobility, however, has the disadvantage that the line end to be inserted must be cut off at the end at an exact right angle, so that there is a uniform contact and deformation of the toothed ring all over the circumference on insertion. A diagonally cut pipe could lead to tilting of the toothed ring because of the undefined freedom of movement and thus to problems on insertion of the pipeline end.
The publication EP 0 160 559 B1 describes a similar pipe connection device in which a toothed or retention ring is likewise mounted so as to be freely movable in its outer circumferential area.
Another document, EP 1 199 506 A1, likewise describes such a connection device, wherein, in contrast to the above publications, the retaining element is held with its outer circumference area basically without axial clearance relative to the connecting element viewed in the direction of an insertion axis of the pipeline end, so that an elastic deformation only occurs in the area of the retaining teeth on insertion or removal of the line end. This clearance-free mounting of the outer circumferential area of the retaining element is associated in practice with a very high manufacturing cost.
All known designs explained above also have the disadvantage that they are only suitable for stable pipelines which can stand the radial retaining forces owing to their intrinsic dimensional stability.